The specular microscope can be used as a simple means of viewing the corneal endothelial morphology of intact human donor eyes. Corneal edema and Descemet's membrane folds are the limiting factors. After nine post-mortem hours, the human cornea has moderate folding which does not severaly restrict endothelial cell observatin. By nineteen hours post-mortem the number of folds has increased to such an extent that specular microscopy is of limited value. Human corneas are being studied to correlate the appearance of the endothelial cells to their viability. The viability is being evaluated by the temperature reversal phenomena which reflects endothelial function. For example, we have been able to correlate the presence of single blister-like swellings of the endothelial cell surface to decreased endothelial cell function. The overall objective of the project is to be able to accurately evaluate corneal endothelial cell viability. This objective has been approached by first establishing the feasibility of observing the endothelium of human donor corneas in eye-bank conditions. Secondly, the donor eye history and the morphology of the endothelial cells was correlated to the cell function. BIBLIOGRAPHIC REFERENCES: Bigar, F., Kaufman, H.E., McCarey, B.E. and Binder, P.S.: Improved Corneal Storage for Penetrating Keratoplasties in Man. Amer. J. Ophthalmol. 79:115-120, Jan., 1975. Bigar, F., McCarey, B.F. and Kaufman, H.E.: Improved Corneal Storage: Penetrating Keratoplasties in Rabbits. Exp. Eye Res. 20:219-222, 1975.